Engine-piston



A. SPlLLMAN-,

ENGINE PISTON. I

APPLICATION FILED FEB. 12. 1919- 1,325,176. Patented Dec. 16,1919.

ALBERT SPILLMAN, OF NORTH TONAWANDA, NEW YORK.

ENGINE-PISTON.

Specification of Letters Patent.

Patented Dec. 16, 1919.

Application filed February .12, 1919. Serial No. 276,465.

To all whom it may concern:

Be it known that I, ALBERT SPILLMAN, a citizen of the United States, residing at North Tonawanda, in the county of Niagara and State of New York, have invented new and useful Improvements in Engine-Pistons, of which the following is a specification.

This invention relates generally to enginepistons, but more particularly to the type of pistons used in internal combustion engines or motors and having a skirt or tubular portion extending rearwardly from the piston-head.

The object of my invention is the produc tion of an inexpensive self-adjusting and non-rattling piston of this kind which may be snugly fitted in the cylinder without danger of scoring it, and which bears uniformly against the cylinder wall around the entire circumference of the piston skirt and practically throughout its length.

In the accompanying drawings:

Figure l is a fragmentary longitudinal section of an internal combustion engine containing the improved piston. Fig. 2 is a transverse section on line 22, Fig. 1. Fig. 3 is a fragmentary longitudinal section on line 3-3, Fig. 1. Fig. 4 is a reduced side elevation of the piston, at right angles to Fig. 1. Fig. 5 is a horizontal section on line 5-5, Fig. 4.

Similar characters of reference indicate corresponding parts throughout the several views.

10 indicates the engine cylinder which may be of any approved construction, and 11 indicates the solid piston head having the customary annular grooves 12 for receiving the packing rings 13.

Extending rearwardly from the piston head is the skirt or tubular body 14 which contains the customary holes or bearings 15 for the piston pin to which the rod 16 is connected. In order to give the skirt the necessary resilience or contractile capacity to pr vent scoring of the cylinder, it is provided at opposite sides with transverse 0r substantially horizontal slits 17 located near the up per end of the skirt, and spiral or diagonal slits 18 extending from one end of the horizontal slits to the rear edge of the skirt, the spiral slits trending in opposite directions, as best shown in Fig. 1. As seen in Fig. 4, the lower or rear ends of the spiral slits preferably terminate at points in line with the centers of the respective piston-pin holes,

smaller in diameter than the skirt, as usual,

and to obtain the best results the narrow portion 140' of the skirt above its horizontal slits 17 is preferably reduced to the same dlameter as said grooved head. In the drawings, this difference in diameter is exaggerated; in practice it usually does not exceed eight-thousandths of an inch in a three-inch piston. A

By this construction, the skirt is rendered resilient around its entire circumference and practically throughout its length. It may therefore be snugly fitted in the cylinder without liability of scoring it, thus obtaining the maximum efliciency of the motor. \Vith this improvement, even after the skirt of a three-inch piston wears about fourthousandths of an inch, it will still fit the cylinder closelyenough to avoid knocking or rattling.

The engine will also continue in reliable operation for a comparatively lon time, inasmuch as little or no oil can Wort past the piston into the top of the cylinder, thereby preventing burning of the oil by the spark and the formation of carbon and avoiding the coating of the spark-plugs'and the production of a smoking exhaust.

Ifthe slitted portion of the skirt be made, say two thousandths of an inch larger in diameter than the cylinder bore, it will act practically as a wide piston-rin or packing, the sections resulting from t e slitting of the skirt being wholly disconnected from each other and unrestrained both in their expanding and contracting movements. The skirt is therefore self-adjusting and free to compensate for variations of diameter due to wear or changes of temperature of the piston and the cylinder, thus maintaining a close, non-rattling fit of the piston 'in the cylinder without causing sticking of the piston or scoring of the cylinder.

This construction and the resulting advantages render the use of aluminum practicable for such pistons, thus securing the additional advantage of lightness.

In the manufacture of the piston, after it has been slitted, the pointed ends of its resilient tongues or sections tend to spring out beyond the true cylindrical line of the piston. To avoid this, they are held in proper position by spot-welding or other suitable means and the surface of the piston is then ground to a true cylinder. The spot-welds are then removed, or if desired, they may be left in place until the piston is shipped to destination, when they are removed by the user.

I claim as my invention:

1. An engine piston having a head and a resilient automatically-expansible skirt extending rearwardly from the head, said skirt being tubular and provided at opposite sides near said head with transverse slits, and spiral slits extending from said transverse slits to the rear edge of the skirt, the two oppositely-tapering sections formed by said slits on the same side of the skirt being I completely disconnected from each other and capable of springing inwardly and outwardly without restraint except by the inclosing cylinder-wall when the piston is in the cylinder.

2. An engine piston having a. head and a resilient automatically-expansible skirt extending rearwardly from the head, said skirt being tubular and provided at opposite sides near said head with transverse slits, and spiral slits each extending from one end of the companion transverse slit to the rear edge of the skirt, the two oppositely-tapering sections formed by said slits on the same side of the skirt being completely disconnected from each other and unrestrained in their contracting and expanding movements, except by the inclosing cylinder-wall, when the piston is in the cylinder.

3. An engine piston having a head and a resilient automatically-expansible skirt extending rearwardly from the head, said skirt being tubu1ar and having piston-pin holes insane at opposite sides, transverse slits formed in the sides of the skirt substantially at right angles to those containlng said holes, and

spiral slits each extending from a point in the rear edge of the skirt substantially in line with one of said holes, to the farther end of one of said transverse slits, the pair of oppositely-tapering sections formed by said slits on the same side of the piston being wholly disconnected from each other and the front section of the pair being likewise disconnected from said head throughout the length of the corresponding transverse slit, said several sections being free to spring in wardly and outwardly wlthout restraint except by the inclosingcylinder-wall when the piston is in the cylinder.

4%. An engine piston having a head and a resilient tubular skirt provided at opposite sides with piston-pin holes, each of the two remaining sides of the skirt comprising resilient automatically-expansible tongues arranged circumferentially of the skirt and extending from a point near'said head to the rear edge of the skirt, adjacent tongues extending in opposite directions from their fixed ends toward their free ends and being disconnected from each other and unrestrained in their contracting and expanding movements, except by the inclosing cylinderwall when the piston is in the cylinder.

5. An engine piston having a head and a tubular skirt extending rearwardly therefrom, said skirt comprising automaticallyexpansible spring-tongues extending in a circumferential series around the skirt, said tongues being integral with said head, adjacent tongues extending in opposite directions from their fixed ends toward their free ends, and the several tongues being disconnected from each other at their adjacent sides from a point near said head to the rear edge of the skirt and unrestrained in their contracting and expanding movements except by the inclosing cylinder-wall when the piston is in the cylinder.

ALBERT SPILLMAN. 

